Pre-coding method and pre-coding device
View Patent ↗Disclosed is a precoding method comprising the steps of: generating a first coded block and a second coded block with use of a predetermined error correction block coding scheme; generating a first precoded signal z1 and a second precoded signal z2 by performing a precoding process, which corresponds to a matrix selected from among the N matrices F[i], on a first baseband signal s1 generated from the first coded block and a second baseband signal s2 generated from the second coded block, respectively; the first precoded signal z1 and the second precoded signal z2 satisfying (z1, z2) T =F[i](s1, s2) T ; and changing both of or one of a power of the first precoded signal z1 and a power of the second precoded signal z2, such that an average power of the first precoded signal z1 is less than an average power of the second precoded signal z2.
1. A transmission method comprising:
selecting one precoding scheme from among N precoding schemes by hopping between the N precoding schemes, for each of a plurality of slots, the N precoding schemes being represented by N precoding matrices F[i] respectively, where i is an integer no less than 0 and no more than N−1, and N is an integer 3 or greater;
applying a power change to a first modulated signal s1 and a second modulated signal s2;
performing a precoding process according to the selected precoding scheme on the first modulated signal s1 and the second modulated signal s2 to which the power change has been applied, thereby generating a first transmission signal z1 and a second transmission signal z2; and
transmitting the first transmission signal z1 and the second transmission signal z2 respectively from a first antenna and a second antenna at the same time at the same frequency, wherein
the precoding matrices F[i] satisfy
F
[
i
]
=
1
α
2
+
1
(
ⅇ
jθ
11
(
i
)
α
×
ⅇ
j
(
θ
11
(
i
)
+
λ
)
α
×
ⅇ
jθ
21
(
i
)
ⅇ
j
(
θ
21
(
i
)
+
λ
+
π
)
)
where λ=0 radians, and α=1,
θ 11 (i) and θ 21 (i) satisfy
e j(θ 11 (x)-θ 21 (x)) ≠e j(θ 11 (y)-θ 21 (y)) for ∀ x,∀y ( x≠y;x,y= 0,1,2 , . . . ,N− 2 ,N− 1), and
the power change involves multiplication of the first modulated signal s1 by a weighting factor u a and multiplication of the second modulated signal s2 by a weighting factor u b that is different from the weighting factor u a .
2. A transmission apparatus comprising:
a selection unit selecting one precoding scheme from among N precoding schemes by hopping between the N precoding schemes, for each of a plurality of slots, the N precoding schemes being represented by N precoding matrices F[i] respectively, where i is an integer no less than 0 and no more than N−1, and N is an integer 3 or greater;
a power changer applying a power change to a first modulated signal s1 and a second modulated signal s2;
a generating unit performing a precoding process according to the selected precoding scheme on the first modulated signal s1 and the second modulated signal s2 to which the power change has been applied, thereby generating a first transmission signal z1 and a second transmission signal z2; and
a transmission unit transmitting the first transmission signal z1 and the second transmission signal z2 respectively from a first antenna and a second antenna at the same time at the same frequency, wherein
the precoding matrices F[i] satisfy
F
[
i
]
=
1
α
2
+
1
(
ⅇ
jθ
11
(
i
)
α
×
ⅇ
j
(
θ
11
(
i
)
+
λ
)
α
×
ⅇ
jθ
21
(
i
)
ⅇ
j
(
θ
21
(
i
)
+
λ
+
π
)
)
where λ=0 radians, and α=1,
θ 11 (i) and θ 21 (i) satisfy
e j(θ 11 (x)-θ 21 (x)) ≠e j(θ 11 (y)-θ 21 (y)) for ∀ x,∀y ( x≠y;x,y= 0,1,2 , . . . ,N− 2 ,N− 1), and
the power change involves multiplication of the first modulated signal s1 by a weighting factor u a and multiplication of the second modulated signal s2 by a weighting factor u b that is different from the weighting factor u a .
3. A reception method comprising:
acquiring a reception signal obtained by receiving a first transmission signal and a second transmission signal respectively transmitted from a first antenna and a second antenna at the same time at the same frequency, the first transmission signal and the second transmission signal having been generated by a predetermined generation process; and
obtaining reception data by performing a demodulation process according to the predetermined generation process on the reception signal,
the predetermined generation process including:
selecting one precoding scheme from among N precoding schemes by hopping between the N precoding schemes, for each of a plurality of slots, the N precoding schemes being represented by N precoding matrices F[i] respectively, where i is an integer no less than 0 and no more than N−1, and N is an integer 3 or greater;
applying a power change to a first modulated signal s1 and a second modulated signal s2; and
performing a precoding process according to the selected precoding scheme on the first modulated signal s1 and the second modulated signal s2 to which the power change has been applied, thereby generating a first transmission signal z1 and a second transmission signal z2, wherein
the precoding matrices F[i] satisfy
F
[
i
]
=
1
α
2
+
1
(
ⅇ
jθ
11
(
i
)
α
×
ⅇ
j
(
θ
11
(
i
)
+
λ
)
α
×
ⅇ
jθ
21
(
i
)
ⅇ
j
(
θ
21
(
i
)
+
λ
+
π
)
)
where λ=0 radians, and α=1,
θ 11 (i) and θ 21 (i) satisfy
e j(θ 11 (x)-θ 21 (x)) ≠e j(θ 11 (y)-θ 21 (y)) for ∀ x,∀y ( x≠y;x,y= 0,1,2 , . . . ,N− 2 ,N− 1), and
the power change involves multiplication of the first modulated signal s1 by a weighting factor u a and multiplication of the second modulated signal s2 by a weighting factor u b that is different from the weighting factor u a .
4. A reception apparatus comprising
an acquiring unit acquiring a reception signal obtained by receiving a first transmission signal and a second transmission signal respectively transmitted from a first antenna and a second antenna at the same time at the same frequency, the first transmission signal and the second transmission signal having been generated by a predetermined generation process; and
an obtaining unit obtaining reception data by performing a demodulation process according to the predetermined generation process on the reception signal,
the predetermined generation process including:
selecting one precoding scheme from among N precoding schemes by hopping between the N precoding schemes, for each of a plurality of slots, the N precoding schemes being represented by N precoding matrices F[i] respectively, where i is an integer no less than 0 and no more than N−1, and N is an integer 3 or greater;
applying a power change to a first modulated signal s1 and a second modulated signal s2; and
performing a precoding process according to the selected precoding scheme on the first modulated signal s1 and the second modulated signal s2 to which the power change has been applied, thereby generating a first transmission signal z1 and a second transmission signal z2, wherein
the precoding matrices F[i] satisfy
F
[
i
]
=
1
α
2
+
1
(
ⅇ
jθ
11
(
i
)
α
×
ⅇ
j
(
θ
11
(
i
)
+
λ
)
α
×
ⅇ
jθ
21
(
i
)
ⅇ
j
(
θ
21
(
i
)
+
λ
+
π
)
)
where λ=0 radians, and α=1,
θ 11 (i) and θ 21 (i) satisfy
e j(θ 11 (x)-θ 21 (x)) ≠e j(θ 11 (y)-θ 21 (y)) for ∀ x,∀y ( x≠y;x,y= 0,1,2 , . . . ,N− 2 ,N− 1), and
the power change involves multiplication of the first modulated signal s1 by a weighting factor u a and multiplication of the second modulated signal s2 by a weighting factor u b that is different from the weighting factor u a .